In an effort to follow tradition (although my recipe isn't 100% traditional) I'd like to attempt to bottle condition with fresh gueuze if possible. Has anyone done this that has some advice? I have about 2 gallons to bottle. To carb to 2.6 vol. it appears I need the equivalent of 2.5oz. of DME (I used DME as it would be closest to pilsner). When I compared that to the gravity of the fresh gueuze (O.G. 1.049), I would need 16-17oz. of wort, based on the volume of water + 2.5 oz. of DME to get to (O.G. 1.049). It sounds right, I just want to verify that I'm calculating it right. Any experience out there would be helpful, thanks.
Wait. Are you talking about using young lambic, as in year old? Or are you saying you are going to make up fresh wort to carb with? It is my understanding that traditionally made gueuze uses "young" lambic for the source of fermentables from which the carbonation is produced. Young lambic being already fermented but not completely so.
Check out this months issue of brew your own, it goes into krausening which I believe is exactly what you're looking for. It even has links to a krausening calculator.